During generation and use of steam, it is often desirable to know the quality of the steam. Various techniques have evolved for measuring steam quality. The more common of these techniques involve using various colorimeters and orifice meters. Other techniques are available utilizing properties of feed water compared to the properties of the liquid phase of the steam. A discussion of these techniques is given in U.S. Pat. No. 3,596,516, issued Aug. 3, 1971. There is still need, however, for a method and apparatus for readily determining the quality of steam.